Practice Lesson of the Week

Giant cell arteritis causing aortic dissection and acute hypertension

BMJ 2008; 337 doi: https://doi.org/10.1136/bmj.39503.769225.BE (Published 04 July 2008) Cite this as: BMJ 2008;337:a426
  1. Yvo M Smulders, consultant internist1,
  2. Dominique W M Verhagen, consultant internist1
  1. 1VU University Medical Center, Division of Internal Medicine, PO Box 7057, Amsterdam 1081HV, Netherlands
  1. Correspondence to: Y M Smulders y.smulders{at}vumc.nl
  • Accepted 2 October 2007

Recent onset hypertension should prompt investigation for secondary causes

Recent onset hypertension should prompt investigation for secondary causes. This search routinely includes screening for mineralocorticoid excess, renal artery stenosis, and, in selected cases, phaeochromocytoma. We present the case of an elderly woman with recent onset hypertension, hypokalaemia, and a raised erythrocyte sedimentation rate. The cause of the hypertension was presumed to be aortic dissection with compromised renal blood flow, but the erythrocyte sedimentation rate provided the clue to the final diagnosis.

Case report

A 74 year old woman was referred because of general malaise and hypertension. During the previous months she had reported fatigue, lack of appetite and weight loss, and muscle weakness. About three weeks before admission she had had sudden onset abdominal pain and diarrhoea, for which no medical aid was sought and which subsided spontaneously after a few days. Her medical history was unremarkable. In particular, her blood pressure had been only mildly raised (160/90 mm Hg, measured repeatedly during previous years, most recently two months before admission).

On examination she had severe hypertension (215/125 mm Hg) but no other abnormalities. Results of vascular, funduscopic, and abdominal examination were normal. Routine laboratory tests showed a raised erythrocyte sedimentation rate (85 mm/h), low plasma sodium (131 mmol/l) and potassium (2.8 mmol/l), moderately raised serum creatinine (111 μmol/l), and mild chronic metabolic alkalosis (arterial pH 7.51, bicarbonate 32 mmol/l). Urinary potassium concentration was 51 mmol/l, and there was no proteinuria or haematuria. A chest x ray and an electrocardiogram were both normal.

She was diagnosed as having hypertension and hypokalaemia. As we suspected that she had primary hyperaldosteronism, we ordered a plasma renin-aldosterone profile and started oral nifedipine and intravenous potassium. Her blood pressure hardly responded to 30 mg of extended release nifedipine (given twice), but adding only 5 mg of the angiotensin converting enzyme (ACE) inhibitor lisinopril caused a sharp drop in blood pressure, from 220/105 to 135/70 mm Hg within two hours. After a few days, the laboratory called to report that her plasma renin activity was very high (30 ng/ml/h; normal value 0.3-3.5 ng/ml/h), with a plasma aldosterone concentration of 1.3 nmol/l (normal value 0.03-0.35 nmol/l). Thinking she might have renal artery stenosis we ordered CT (computed tomography) angiography, which showed an aortic dissection (type B: originating distal to the left subclavian artery; fig1). The coeliac trunk and superior mesenteric artery originated from the false lumen, which ended at the level of the right renal artery. The left renal artery was stenotic with signs of atherosclerosis, with an atrophic left kidney. The surgeon decided not to operate on the aorta because no acute or alarming symptoms (pain, leakage, critical organ ischaemia) were present. Groin pulsations and leg arterial pulsations and pressure were rechecked and were found to be normal. She was further treated with low dose ACE inhibitors. Syphilis was excluded by serological tests.

Figure1

Fig 1 Frontal plane reconstruction of computed tomography angiography, showing the thoracic part of a type B aortic dissection

Her further clinical course was uneventful. When we reviewed her case before scheduled discharge, we again noted the raised sedimentation rate, which had persisted throughout admission. The combination of a high sedimentation rate and aortic disease in an elderly woman triggered our suspicion of giant cell arteritis. Although her temporal arteries seemed completely normal, we took a 2 cm biopsy from the right temporal artery. Microscopic examination showed classic signs of giant cell arteritis (fig 2). She was treated with prednisone 60 mg daily. A year after she was admitted, she was doing well with 5 mg of prednisone and a low dose ACE inhibitor. Her erythrocyte sedimentation rate was 17 mm/h and her blood pressure 140/80 mm Hg.

Figure2

Fig 2 Cross section of temporal artery biopsy. Main panel (HE stain, magnification 250×) shows marked intimal hyperplasia. Circled area shows periadventitial inflammatory cells (mainly histiocytes and lymphocytes) invading the adventitia. Top right corner (immunohistochemical staining of the encircled area for CD68 positive cells) shows predominance of histiocytes, including giant cells

Discussion

We believe that this patient had symptoms associated with her vasculitis during the months before admission. The aortic dissection may have explained her abdominal pain and diarrhoea (transient intestinal ischaemia) and was presumably responsible for compromised perfusion of the right kidney, which caused high renin, new onset hypertension. The left kidney was atrophic, suggesting longstanding renovascular disease, which had not caused hypertension before she developed aortic disease. Thus, an important lesson is that acute hypertension, in particular with signs of activation of the renin-angiotensin-aldosterone system (hypokalaemia, mild hyponatraemia, hyperreninaemia, strong blood pressure response to ACE inhibition or angiotensin receptor blockade), should trigger suspicion of aortic disease, especially in elderly people. Aortic dissection can present with few symptoms and be easily overlooked. Hypertension occurs in about half of patients with aortic dissection and may be caused by “pseudo-coarctation” (flow reduction through the true lumen, resulting in upper body hypertension) or involvement of the renal artery, or both. However, many cases seem to be idiopathic.1 Marked hyperreninaemia, as in our patient, is compatible with renal hypoperfusion, which may point towards both pseudocoarctation or renal artery involvement.

A second important lesson from this case is that aortic disease in an elderly patient with a high erythrocyte sedimentation rate should lead to consideration of giant cell arteritis. This disorder is also known as temporal artery arteritis and is most common in women over 50 (incidence 20-30 per 100 000).2 About 10-15% of patients with temporal arteritis have clinically manifest aortic involvement, which presents as aneurysm or dissection of the aorta.3 Aortic inflammation may represent a distinct clinical subtype of giant cell arteritis, but the pathogenic mechanism is probably similar to other subtypes.4 A histopathological study showed that aortic involvement occurs frequently but has a subclinical course in most patients.5 A recent study using positron emission tomography confirmed that subclinical inflammatory involvement of the aorta in patients with temporal arteritis or polymyalgia rheumatica is common: up to 75% of cases have abnormal findings suggesting aortic wall inflammation.6 Positron emission tomography may be particularly useful to identify aortic inflammation in people who have negative findings on temporal artery biopsy, as obtaining a biopsy from the aorta to confirm the diagnosis is often not possible. Apart from infectious aortitis, Takayasu disease is important in the differential diagnosis but usually presents at an earlier age and does not affect the temporal arteries.

In our experience, it is not uncommon for aortic giant cell arteritis to present without signs of temporal arteritis or abnormal temporal artery histology.7 This case shows that even though a temporal artery seems normal, a biopsy is needed when there is clinical suspicion of giant cell arteritis. Recent onset hypertension in elderly patients may point towards aortic disease, and aortic disease, especially in combination with an acute phase reaction, may the presenting sign of giant cell arteritis.

Notes

Cite this as: BMJ 2008;337:a426

Footnotes

  • Contributors: Both authors contributed equally to the manuscript. YMS is the guarantor.

  • Funding: None.

  • Competing interests: None declared.

  • Provenance and peer review: Not commissioned; externally peer reviewed.

References

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